The present invention relates to a steering lock assembly which is designed to prevent a return of a key from an unlock position thereof to a lock position unless a special knob is manually operated.
Steering lock assemblies of the type described have been proposed for safe driving of automotive vehicles and actually put to practical use on some modern automotive vehicles.
In one of such prior art steering locks, a rotor integral with a key cylinder is partly notched to have a cam section which is selectively engaged by a member adapted to obstruct the rotation of the rotor. The stop member is manually pushed up or down to permit a key to be rotated to a locking position.
This type of steering lock is furnished with a safety device (e.g. a pivotal lever) so that a simple turn of the key to the lock position cannot cause the steering shaft to be locked in position. That is, the locking bolt cannot advance into locking enagement with a recess of the steering shaft unless the key is drawn out from the steering lock.
During a downhill drive of an automotive vehicle, for example, such a structure maintains the steering shaft still rotatable even when the key is turned to the lock position and thereby eliminates an accident.
It is not unusual for an operator to habitually pull out a key from the steering lock once the operator turns it to the lock position. Due to this habit, the operator may draw out the key even when the vehicle is in travel, as during a downhill drive.
Such a situation is potentially dangerous since the steering shaft would be locked in position.
With this in view, there has recently been proposed a steering lock assembly which permits the key to be turned to the lock position only when the turn of the key to said position is preceded by an operator's additional and intentional action, i.e. manipulation of the stop member.
However, all the prior art steering lock assemblies discussed above cannot fully achieve the object due to some unavoidable drawbacks.
For instance, the structure is disproportionately intricate. Meanwhile, the knob on the stop member or manual actuator is located near the key insertion position to allow easy access of the one hand which is operating the key. This may cause the key and stop member to be subjected to unintentional one-hand operation which would lead to an accident as previously mentioned.